[type]
Parser
[grammar]
grammar T;
r
: (a b | a) EOF {<writeln("$text")>}
;
a
: X Y?
;
b
: Y
;
X: 'X';
Y: 'Y';
WS : [ \r\n\t]+ -> skip ;
[start]
r
[input]
X Y
[output]
"""XY
"""
[errors]
"""line 1:3 missing 'Y' at '<EOF>'
"""
[flags]
predictionMode=SLL